June 2009 - Boost-users - lists.boost.org

indirect_iterator,symmetric_matrix and ptr_vector
by Archie14 01 Jun '09

01 Jun '09

Following test fails to compile. Errors start with the first call to make_indirect_iterator. On the first glace on the error output it looks that indirect_iterators cannot be used together with ptr_vector and matrix. Is that correct? If I need to calculate the sum of all matrices in a vector - what is the right way to do it? void test() { typedef symmetric_matrix<double, lower> matrixofdoubles; boost::ptr_vector<matrixofdoubles> lst; boost::make_indirect_iterator(lst.begin()); // testing ind.iter. matrixofdoubles totalsum (10); std::accumulate( boost::make_indirect_iterator(lst.begin()), boost::make_indirect_iterator(lst.end()), totalsum, std::plus<matrixofdoubles>()); } Errors are: c:\Libraries\boost\boost_1_39_0\boost/pointee.hpp(30) : error C2039: 'element_type' : is not a member of 'boost::numeric::ublas::symmetric_matrix<T,TRI>' with [ T=double, TRI=boost::numeric::ublas::lower ] c:\Libraries\boost\boost_1_39_0\boost/mpl/eval_if.hpp(41) : see reference to class template instantiation 'boost::detail::smart_ptr_pointee<P>' being compiled with [ P=boost::numeric::ublas::symmetric_matrix<double,boost::numeric::ublas::lower> ] c:\Libraries\boost\boost_1_39_0\boost/pointee.hpp(69) : see reference to class template instantiation 'boost::mpl::eval_if<C,F1,F2>' being compiled with [ C=boost::detail::is_incrementable<boost::numeric::ublas::symmetric_matrix<doubl e,boost::numeric::ublas::lower>>, F1=boost::detail::iterator_pointee<boost::numeric::ublas::symmetric_matrix<doub le,boost::numeric::ublas::lower>>, .. etc.

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google.stringencoders vs (boost.string_algo & boost.lexical_cast)
by Roman Shmelev 01 Jun '09

01 Jun '09

Hi! stringencoders are told to be 2x faster than std approaches. But what about boost? Has somebody tested the performance of both libraries? I mean toLower, toUpper, itoa, dtoa functions. Thank you

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multi_array_ref (lack of) default constructor
by gtsml owevwr 01 Jun '09

01 Jun '09

Hi, Does anybody know why multi_array_ref doesn't have a default constructor? I'm asking because I wanted to make a multi_array of multi_array_ref and that doesn't seem to be possible because multi_array expect the element type to be default constructible. Thanks, Frank

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Re: [Boost-users] boost::serialization and PHP websites
by Brian Wood 31 May '09

31 May '09

Pascal Kesseli writes: > Currently, I consider the > boost serialization a de-facto standard for C++ serialization issues. In 2007 it wasn't a stretch to say that General Motors was a de facto standard in the automobile industry. Now they want 70 billion from taxpayers. Oh my G-d! -- Brian Wood Ebenezer Enterprises www.webEbenezer.net "Then Samuel took a rock and set it up between Mizpah and Shen. He named it Ebenezer [Rock of Help] and said, 'Until now the L-RD has helped us.'"

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